The present invention relates to acid cation exchange resins (synthetic acid resin catalyst) and in particular to a process for obtaining structures of these materials.
The present inventor has recently developed a novel process applicable to several types of chemical reactions. One of these is disclosed in U.S. application Ser. No. 928,397, filed July 27, 1978. Briefly, that process is the separation of isobutene from a C.sub.4 feed stream by using an acid cation exchange resin as a distillation column packing wherein the isobutene is dimerized and recovered as a bottom fraction and the other C.sub.4 's in the stream leave the top of the column.
To carry out this new process, the known acid cation exchange in granular form was sown into pockets in a cloth belt, and the belt wrapped around a wire mesh for support. This system worked, however, it is apparent that those shapes and form designed for use as distillation packing material would be superior. Various attempts were made to attach granular resin to distillation saddles, and to dissolve the cation resin in a suitable solvent and coat the desired shape therewith. However, neither method worked. The catalyst with the cation resin attached was very delicate and a solvent could not be found. Furthermore, extruding the cation exchange resin into desired shapes is not possible, since these materials are generally not heat stable at temperatures above 125.degree. C. (Amberlyst Xn-1011 is reported to have a useful life at 175.degree.-200.degree. C.), however, at temperatures higher enough to extrude the materials they would be substantially deactivated.
The acid cation exchange resins are well known and are available in granular form from several sources. The catalyst contain sulfonic acid groups and are obtained by polymerization or copolymerization of aromatic vinyl compounds followed by sulfonation.